1. Field of the Invention
The present invention relates to a control for controlling the shifting of an input section of a vehicular compound transmission. In particular, the present invention relates to a control for controlling the shifting of a synchronized, splitter-type input section of a compound transmission having a manually shifted, preferably synchronized, main transmission section and a remote selector for selecting/preselecting an engaged input section ratio.
More particularly, the present invention relates to a control of the type described above wherein, upon disengagement of the vehicle master clutch and disengagement of the main transmission section, the input section is automatically shifted into a nonengaged or neutral position which will reduce the time and forces necessary to synchronize and shift the main transmission section. Further, the control will retain the input section in the nonengaged condition until a main transmission section ratio is engaged, except for an instantaneous shift engagement and then disengagement of an input section ratio, preferably, low speed ratio, upon engagement of the master clutch to allow rotation of the main section synchronizer blockers off the blocked condition/position thereof for start from stop gear engagement.
2. Description of the Prior Art
Compound mechanical transmissions of the input splitter type and compound transmissions utilizing input auxiliary sections are known in the prior art as may be seen by reference to U.S. Pat. Nos. 2,886,982; 3,741,035; 4,485,692; 4,882,951; and 4,831,894, the disclosures of all of which are hereby incorporated by reference. Compound transmissions of the splitter or range type, or a combination thereof, are well known in the prior art as may be seen by reference to U.S. Pat. Nos. 3,105,395; 4,735,109; and 4,788,889, the disclosures of all of which are hereby incorporated by reference.
Automatic and semi-automatic transmission and clutch controls are known in the prior art as may be seen by reference to U.S. Pat. Nos. 4,081,065; 4,361,060; and 4,648,290, the disclosures of all of which are hereby incorporated by reference. Synchronized mechanical change gear transmissions and transmission sections are well known in the prior art as may be seen by reference to U.S. Pat. Nos. 4,018,319; 4,373,403; and 4,432,251, the disclosures of all of which are hereby incorporated by reference.
While compound mechanical (i.e., engaging ratios by means of positive clutches) heavy duty vehicular change gear transmissions of the synchronized type having input auxiliary sections of the splitter type are known, such transmissions have required an undesirably large effort and/or period time to achieve main section shifting, and have not automatically disengaged and/or reengaged the input section under specified conditions, and require expensive and/or complicated shift assist mechanisms and/or have required a disconnect member with relatively complicated controls therefor.